JP2864772B2 - Method and apparatus for conveying powdered solid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for transferring powder solids, and more particularly to a method and an apparatus for quantitatively transferring powder solids to a high pressure place without using mechanical means.

[0002]

2. Description of the Related Art Conventionally, as a means for quantitatively transferring powdered solid (or dust) under pressure, a rotary feeder,
In many cases, a method of quantitatively discharging the hopper from each hopper by a mechanical means such as a screw feeder and allowing the hopper to freely fall, and then forcibly supplying the hopper with a carrier gas into a transfer destination is adopted. A typical example is shown in FIG. In the figure, an example in which a transport system using a combination of mechanical means and a carrier gas is used for both a raw coal supply system and a char circulation system in a coal treatment process, particularly a char supply system will be described in detail.

As shown in the figure, a cyclone 19, a cyclone hopper 20, a char recovery hopper 21,
It comprises a particle supply pipe connecting the char supply hopper 26 and each hopper, switching valves 61 and 50, a rotary feeder 8 ', and load cells 22 and 24 for weighing. The cyclone 19, the cyclone hopper 20, the char recovery hopper 21, and the char supply hopper 26 are connected in this order.

[0004] After being separated into product gas and char (or dust) by the cyclone 19, the recovered char 23 is
After entering the char collection hopper 21, the collection amount is grasped by a load cell 22 installed on the outer wall of the char collection hopper 21. When the char 23 is filled in the hopper 21, the valve 50 is closed, the pressure of the char recovery hopper 21 is made equal to or slightly higher than the pressure of the char supply hopper 26, and then the valve 62 is opened. Transfer to After filling the hopper 26, the valve 62 is closed, the pressure of the recovery hopper 21 is made equal to the pressure on the furnace side 17, and then the valve 50 is opened to start a steady operation. Repeat the above operation. It is quantitatively discharged from the char supply hopper 26 into the furnace 17 by using a rotary feeder 8 ', dropped freely, and then supplied to an ejector 35' to be transferred by a carrier gas (inert gas or generated gas) 9 '. The high-temperature char 23 flows through the char transfer pipe 29, and the furnace 1 passes through the char burner 16.
7 is a lock hopper type dry solid supply method for supplying into the inside 7. The coal supply system is also a dry solid supply method employing a lock hopper method, and is similar to the char supply method.

When this dry technique is used for pressurization, the following problems occur.

(1) In the discharging method from a hopper by a mechanical means (a rotary feeder or the like), a bridge is formed at an outlet of the hopper depending on a kind of raw material, a raw material particle diameter, a packing density, and the like, and in many cases, the bridge is not discharged at the time of discharging. Therefore, as a measure for preventing bridge formation or the like, it is necessary to apply vibration, aeration, mechanical stirring, or the like to the supply hopper by a vibrator, and it is necessary to add extra equipment.

(2) Since the pressure of the apparatus itself is high, gas leaks from the seal section of the feeder section, and the supply is stopped. In particular, since the temperature of the char 23 scattered from the furnace 17 in the char circulating system is as high as 400 ° C. to 600 ° C., the char circulating system is heated and maintained by a heater or the like so that the char does not condense. For this reason, it is difficult to supply a higher temperature than the coal supply system of normal temperature specifications, and the sealing member is loosened due to the influence of heat or the like, and the occurrence of gas leakage is high.

(3) Since the lock hopper system is used,
Since at least three supply hoppers are required, the operation procedure (transfer from the collection hopper to the supply hopper, etc.) becomes complicated, the operation takes time, and the number of devices attached to each hopper increases, resulting in cost. Is high.

According to (1) and (2), if the raw material cannot be supplied stably, it may cause an adverse effect on the combustion efficiency and the stable operation. In addition, there is a demand for a transporter that can suitably transport even when supplying to a high-pressure container. In addition, simplification of the char circulating system is desired according to (3).

Conventionally, as a means for stably transferring a powdered solid without using mechanical means, the following methods are typical.

(1) Ejector type supply device. A method in which a gas fluid is ejected from a nozzle at a high speed to generate a vacuum near an opening, and a powder solid is transferred using the vacuum (Japanese Patent Application Laid-Open Nos. 51-24189 and 55-17729) ).

(2) Pressure feeder. A system in which compressed air is continuously fed to a riser at a large mixing ratio (JP-A-46-24854).
No.).

(3) There is a method of transporting a solid powder by a high-speed swirling flow in a pipe (Japanese Patent Application Laid-Open No. Sho 60-31437).

[0014]

As a method for stably supplying a raw material by a dry supply method, in the above-mentioned method (1), when a pressure fluctuation occurs at the inlet and outlet sides of the ejector, the phenomenon of pooling in the pipes occurs. Occurs and a continuous flow cannot be obtained. In addition, there is a drawback that the structure of the nozzle portion in the ejector is complicated because the flow rate for ejecting the ink at a high speed and the structure for generating a vacuum near the opening need to be devised.

In the case of transporting high-temperature char,
It is important to discharge the char from the hopper quantitatively at all times so that the char is not condensed. However, it is conceivable that the discharge from the hopper is stopped without natural fall due to pressure fluctuation in the ejector. For this reason, it is common to make the pressure on the supply hopper side higher than the pressure on the furnace side, or to combine it with a mechanical means such as a rotary feeder to minimize the influence on the pressure fluctuation to perform a constant discharge. is there. However, even in this method, as described above, in order to avoid a bridge or the like at the outlet of the hopper, unless the countermeasures such as a vibrator and aeration are taken, the discharge becomes impossible in many cases.

In the method (2), when the hopper side pressure and the furnace side pressure fluctuate, the supply amount becomes unstable. Also,
Since the supply amount is controlled by the pressure difference, the supply amount changes greatly even when the pressure slightly changes. Therefore, it is effective when the supply amount is largely changed, but there is a disadvantage that it is difficult to adjust a small amount.

The method (3) is suitable for conveying particles having a large particle diameter, but has a drawback that particles having a particle diameter of 40 μm or less are conveyed only at the central portion and accumulate on the inner wall side of the tube.
In addition, since the gas supply port has a double structure for forming a swirling flow in the transport pipe, the transport pipe has a complicated structure.

An object of the present invention is to provide a method and an apparatus for transporting a powdered solid which have a simple structure of a powdered solid transporter and which can be stably supplied to a high-pressure container with a small transporting gas amount without using mechanical means. To provide.

[0019]

SUMMARY OF THE INVENTION According to the present invention, a cyclone (or a swirl type feeder) in which a powder solid and a generated char are forcibly formed by a powder solid conveyer (or a swirling type feeder) which forms a swirling flow without using mechanical means. The char is sucked from the cyclone lower hopper, and the char is continuously discharged from the cyclone (or the cyclone lower hopper), and at the same time, it can be stably and continuously supplied to a high pressure furnace.

That is, an inflow pipe through which powder solids and chars flow into cylindrical and conical containers is installed at the center of the upper part of the carrier, and a carrier gas (inert gas or generated gas) forms a swirling flow in the carrier. A plurality of carrier gas supply units are arranged in the direction in contact with the outer wall of the carrier so as to cause the powder solid and the carrier gas (inert gas or generated gas) to be provided on the inner wall side of the lower part of the carrier. The char can be stably supplied to a furnace having a high pressure.

Further, by installing the transporter directly below the cyclone (or below the cyclone hopper), the attached equipment is simplified.

Further, a stable supply method when the carrier is attached to the combustion device char circulation system is provided by installing a pressure difference monitoring device for monitoring a difference between the furnace side pressure and the carrier pressure, and when the load changes and the furnace side pressure. When the supply amount changes during the fluctuation, the pressure inside the carrier is adjusted by manipulating the carrier gas amount (swirling gas amount) so that the difference between the furnace side pressure and the carrier pressure becomes constant, and the powder solids are adjusted. And the like, to control the amount of supply, thereby enabling stable supply.

[0023]

The powder solid carrier of the present invention utilizes the pressure difference generated in the carrier by the swirling flow of the carrier gas (inert gas or generated gas) 9 '.

That is, an inflow pipe through which powder solids and chars flow into cylindrical and conical vessels is provided at the center of the upper part of the carrier, and a carrier gas (inert gas or product gas) supply part is provided with a swirling flow in the carrier. A plurality of tubes were arranged in the direction in contact with the outer wall of the carrier so as to be formed, and a discharge tube for discharging powder solid, char, and carrier gas (inert gas or generated gas) was provided on the inner wall side of the lower portion of the carrier. FIG. 10 shows a pressure distribution when a swirling flow is generated in the transfer device by the transfer gas (swirl gas). As shown in the figure, the pressure at the center is low, and the pressure distribution near the wall is high. As described above, when the swirling flow is generated, a negative pressure is generated at the center, and the pressure near the wall increases. By taking advantage of this, a discharge port (or inlet) from the hopper is installed at the center where negative pressure is generated, and particles in the cyclone (or cyclone hopper) are forcibly sucked, and the high pressure portion on the wall side And a discharge port for a mixed-phase flow of powdered solids + carrier gas was provided.

An operating factor for controlling the char supply amount is as follows:
This is the amount of the transfer gas (inert gas and generated gas) of the powder solid transfer device. FIG. 11 shows the relationship between the amount of discharged char, the pressure in the carrier and the amount of carrier gas. As shown in the figure, as the transport gas amount F increases, the char discharge amount and the transport inner wall side pressure increase, so that the supply amount can be controlled. This result is a condition when the furnace-side pressure is fixed at P = 4 atg. When the furnace-side pressure changes, the supply amount inevitably also changes. Therefore, in order to supply the char stably, a pressure difference monitoring device for monitoring the difference between the furnace side pressure and the carrier side pressure is installed, and the char can be supplied stably by controlling the pressure difference as a guide. Confirmation of the char transfer amount at regular time is performed by monitoring the indicated level of the transfer pressure and the differential pressure between the cyclone and the transfer device and the differential pressure between the transfer device and the char transfer pipe, and transmitting the signal to the arithmetic unit. Depending on the level difference, it is transmitted from the supply amount control device to the carrier gas control valve to adjust the carrier gas amount. By performing such an operation, more precise control becomes possible. Therefore, by using a powder solid transporter, a pressure difference monitoring device and a supply control device without using mechanical means, the powder solids can be transported stably and the transporter is installed at the lower part of the cyclone. Is simplified.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to FIGS. FIG.
Alternatively, FIG. 2 shows a schematic diagram of the apparatus when the present invention is used. FIG. 2 has the same effect as that of FIG. 1, in which a solid powder carrier is installed below the cyclone via a hopper with a load cell. Details will be described with reference to FIG. This system consists of a coal supply system, a combustion furnace, and a dust collection system. The pulverized pulverized coal 3 is stored in a raw material supply hopper 5 and sent to an ejector 35 by a feeder 8. The transfer gas (inert gas or generated gas) 9 is mixed with the pulverized coal 3 in the ejector 35 and supplied from the transfer pipe 10 to the combustion furnace 17 through the raw material burner 12. Within 17, for example,
Dispersion plate 57 for fluidizing limestone particles 56 as fluidizing medium
Coal and air are supplied to the fluidized bed forming section having the above, and are burned in an oxidizing atmosphere. Further, a heat exchanger 60 for heat recovery was installed. The experiment was performed by setting the inside of the combustion furnace 17 to 850 ° C.

Although ash was generated during the experiment, the ash was allowed to fall freely, passed through the ash distribution line 36, and passed through the ash collection hopper 3
7, and then discharged. Combustion furnace 17
Is a pressurized container having a dispersion plate 57 in the lower part of the furnace 17.

The combustion gas is supplied to the combustion gas flow control valve 14.
After the flow rate is set via the gas supply line 13 and supplied through the gasifying agent supply line 13, the gas is supplied from the lower part of the dispersion plate 57 in the lower part of the combustion furnace 17. Since the generated gas also contains char 23 containing unburned carbon, a char and a cyclone 19 for dust collection are installed at the outlet of the combustion furnace 17 to separate the gas and char. The gas flows through the cyclone outlet line 28 to the high temperature dedusting system.

The dust collecting system includes a cyclone 19 (cyclone hopper 20), a powder solid carrier (char feeder) 27,
Carrier pressure detector 54, carrier gas (inert gas and generated gas) 9 ', char carrier pipe 29 and char burner 16
Consists of

Further, the stable char transfer control system includes an arithmetic unit 3
3, a control device 34 for controlling the operating factors and a pressure difference monitoring device 41 for monitoring the pressure difference between the furnace side pressure and the carrier pressure.

Next, the details of the powder solid transporter 27 will be described. FIG. 3 is a cross-sectional view of the powder solid transporter of the present invention, and FIG. 4 is a view taken in the direction of arrows IV-IV in FIG. The whole is composed of an inflow portion 42 of the powder solid 23, a carrier gas (inert gas and generated gas) supply portion 43, a swirling portion 48, and a discharge portion 45 for discharging a mixed-phase flow 47 of the carrier gas and the powder solid 23. Inflow section 42
Is in the upper center of the transporter 27. Carrier gas supply unit 4
No. 3 was installed in a tangential direction with respect to the outer wall of the transporter so as to form a swirling flow in the transporter 27. In this case,
Four were installed. The discharge unit 45 is provided one on the inner wall side of the lower part of the cylinder of the transporter 27.

The powdered solid (char) 23 is sucked into the inflow section 42. Here, the operation in the turning section 48 will be described. The powdered solid 23 passes through the inflow section 42 and turns 46
to go into. Due to the swirling flow 47 formed by the carrier gas, the powdered solid 23 swirls strongly in the swirling part 48 and flows downward of the cylinder. This strong turning lowers the pressure near the axis and increases the pressure near the wall. Therefore, the powder solid is forcibly sucked from the inflow portion 42 of the powder solid 23 near the axis, and there is no adverse effect such as formation of a bridge at the outlet of the hopper.
In addition, since the high-pressure part in the swirling part 48 is discharged to the low-pressure part at the outlet of the discharge part 45, it can be supplied stably.

FIGS. 5 to 8 show a structure having the same effect as that of FIG.

Next, a description will be given of a transfer method when the powder solid transfer device 27 of the present invention is provided. FIG.
FIG. When starting the combustion furnace,
A predetermined amount of the carrier gas (inert gas or generated gas) 9 ′ is circulated in advance from the carrier gas supply unit 43, and it is determined that the char carrier pipe 29 is not blocked by the carrier 27 and the discharge pipe 4.
It confirms by the differential pressure level of the differential pressure gauge 51 installed between five. The flow rate was set such that the gas flow rate in the discharge section 45 was 6 to 7 m / s. Thereafter, when the raw material 3 is supplied from the coal supply system, a char containing unburned carbon is generated together with the generated gas, so that the char 23 is collected by the cyclone 19. The char 23 is transferred to the carrier 27 of the present invention.
And forcedly supplied into the furnace 17 with high pressure. The pressure of the carrier at this time is slightly higher than the pressure on the furnace side when the pressure of the carrier is monitored by the carrier pressure detector 54. Raw material 2
3 is the differential pressure 51 between the carrier and the discharge section gradually at the same time as the supply.
(In FIG. 2, the weight of the hopper load cell 25 is reduced), and the amount of carrier gas is set so as to have a predetermined pressure difference. During normal operation, the cyclone 19 and the transporter 27
The differential pressure level (including the weight change of the hopper load cell 25 in FIG. 2) of the differential pressure gauge 52 installed between the transfer device 27 and the discharge unit 45 is monitored, and supplied stably. I confirmed that. The supply amount control device 34 is provided in advance for the indicated values of the differential pressure gauges 51 and 52 or the load cell 55.
If there is a slight deviation from the set value stored in the control unit, it is determined that the supply amount has changed, and a signal is transmitted to the carrier gas control valve 15, which is a control factor, to adjust the carrier gas amount. Was controlled.

At the time of shutdown, after the raw material 3 is stopped, the char stored in the cyclone 19 and the like is supplied into the furnace 17 and circulated until the indicated differential pressure level of the differential pressure gauges 51 and 52 returns to the level of only gas. . The carrier gas (inert gas or generated gas) circulated to the end for lowering the temperature in the furnace 17 and replacing the gas.

Also, if the furnace pressure and the carrier pressure change, the supply amount varies greatly and the supply amount control becomes unstable, so it is important to keep the difference between the furnace pressure and the carrier pressure constant. It is. Therefore, a pressure difference monitoring device 41 that monitors the pressure difference between the pressure detected by the furnace pressure detector 53 and the pressure detected by the carrier pressure detector 54 is installed, and in a steady state, the operation is performed with a constant pressure difference, When the pressure on the furnace side fluctuates, the pressure in the carrier also fluctuates. Therefore, the char is supplied stably by operating the carrier gas regulating valve 15 and adjusting the carrier gas amount based on the signal of the pressure difference monitoring device 41. .

The powder solids carrier can be used not only in a combustion furnace, a boiler, a gasification furnace and the like but also in all powder solids supply systems.

[0038]

According to the present invention, gas and powder solids are swirled in the powder solids transporter to be forcibly sucked from the inlet pipe, so that there is no stagnation of particles on the inlet side, and the discharge pipe is Since a high pressure difference can be provided between the swirling chambers, there is no blockage at the transporter outlet, and stable and continuous supply is possible. In addition, by installing a pressure difference monitoring device and a supply control device that monitors the pressure difference between the furnace side pressure and the carrier side pressure, even if the pressure fluctuates, the responsiveness to the change becomes faster, and Becomes possible.

[Brief description of the drawings]

FIG. 1 is a system diagram of the entire apparatus when a transporter of the present invention is attached to a lower part of a cyclone.

FIG. 2 is a system diagram when a hopper is attached to a lower part of the cyclone of FIG. 1;

FIG. 3 is a cross-sectional view of the powder solids transporter of the present invention.

FIG. 4 is a view taken in the direction of arrows IV-IV in FIG. 3;

FIG. 5 is a cross-sectional view of a powder solid transporter having the same effect as the present invention.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 5;

FIG. 7 is a cross-sectional view of a powder solid transporter having the same effect as the present invention.

8 is a sectional view taken along the line VIII-VIII in FIG. 7;

FIG. 9 is a system diagram when the present invention is attached to a char transfer system.

FIG. 10 is a pressure distribution diagram in a powder solid carrier.

FIG. 11 is a characteristic diagram of a relationship between a raw material supply amount, a carrier pressure, and a carrier gas amount.

FIG. 12 is a conventional system diagram.

[Explanation of symbols]

3 ... powder solid, 5 ... raw material supply hopper, 8 ... rotary feeder, 9 '... conveying gas, 10 ... raw material conveying pipe, 12 ... raw material burner, 13 ... gasifying agent supply line, 14 ... combustion gas flow control valve, 15 ... Conveying gas control valve, 16 ... Char burner, 17 ... Combustion furnace, 18 ... Gasification furnace outlet line, 19 ...
Cyclone, 20: cyclone hopper, 21: char recovery hopper, 23: char (or coke), 27: powder solids transporter, 34: supply amount control device, 41: pressure difference monitoring device, 43: transport gas supply unit, 45 ... release part, 46 ...
Powder solid + carrier gas.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-57-137223 (JP, A) JP-A-58-135032 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B65G 53/00-53/66 B04C 5/18

Claims (4)

(57) [Claims] 1. A swirling flow is formed in a powder solid by a carrier gas.
Into the formed carrier, and from one part of the carrier
Powder solids that release gas-conveyed powder solids
In the transfer method, the transfer gas is transferred to a side of the transfer device.
Tangentially supplied from a plurality of locations and transported into the transporter
A horizontal swirling flow is formed by the gas, and the pressure in the transporter is increased.
The powder solid falls from above the center of the swirling flow where the force becomes low
Supply, the pressure inside the transporter becomes lower
To release the powdered solid that has been gassed towards
A method for conveying powdered solids, characterized in that: 2. A swirling flow is formed by a carrier gas from a powder solid.
Into the formed carrier, and from one part of the carrier
Discharges gas-conveyed powder solids and conveys them to combustion furnace, etc.
In the method for transporting a solid powder, the transport gas
Tangentially from multiple locations on the side of the carrier
To form a horizontal swirling flow in the carrier,
From above the center of the swirling flow where the pressure of
Drop feeding, the outer circumference of the swirl flow where the pressure inside the transporter becomes high
Release the powdered solid that has been transported gas downward
Conveyed to the combustion furnace, etc.
Detects the difference from the pressure inside the combustion furnace and makes the difference constant
To adjust the amount of carrier gas supplied to the carrier.
A method for conveying powdered solids, characterized in that: 3. A carrier gas supply section and a powder solid around the container.
Supply section and a discharge section for the powdered solids conveyed by gas.
As a result, a swirling flow due to the carrier gas is formed in the container.
In the powdery solid transport device, the side of the container
Tangentially provided carrier gas supply units at a plurality of
So that the swirling flow by the gas supply is formed in the horizontal direction,
The powder is located above the center of the swirling flow where the pressure in the container decreases.
A swirl flow in which a solid supply section is provided and the pressure inside the container increases
The powdered solid that has been transported downward from the outer periphery is released.
Gas to one place located on the outer circumference of the swirl flow
Powder provided with a discharge section for powder solids to be fed
A device for transporting solids. 4. A carrier gas supply section and a powder solid around the container.
Supply section and a discharge section for the powdered solids conveyed by gas.
So that a swirling flow due to the carrier gas is formed in the container.
And the powder solids discharged from the container together with the carrier gas
Powder solids conveyed to the combustion furnace by a conveying pipe
Tangent to a plurality of locations on the side of the container.
A supply section for the carrier gas is provided in the direction, and swirling by the carrier gas
The flow is formed horizontally and the pressure in the vessel is
The powder solid supply section is installed above the center of the swirling flow
From the outer periphery of the swirling flow where the pressure in the container increases.
So that the powdered solid transported by
A discharge section for the powdered solid to be conveyed,
Pressure difference monitoring device for monitoring the pressure difference between the force and the pressure of the combustion furnace
Into the container based on the signal of the pressure difference monitoring device.
Means for adjusting the amount of carrier gas to be supplied.
A powder solid conveying device, characterized in that it is provided.